Messages in this thread Patch in this message | | | From | Janusz Krzysztofik <> | Subject | [PATCH 5/5 v2] ARM: OMAP1: recalculate loops per jiffy after dpll1 reprogram | Date | Tue, 29 Nov 2011 01:25:32 +0100 |
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Otherwise timing is inaccurate, resulting in devices which depend on delay(), like omap-keypad, broken.
Created and tested on top of linux-omap/fixes on Amstrad Delta.
Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> --- Hi, This version no longer depends on changes to init/calibrate.c, using the method kindly advised by Russell instead. Then, patch 4/5 can be dropped.
However, the result of cpufreq_scale() differs from that of (re)calibrate_delay() by ca. 6%, i.e., 70.40 vs. 74.54. Please advise if this approximation is acceptable.
Thanks, Janusz
arch/arm/mach-omap1/clock_data.c | 7 ++++++- 1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/arch/arm/mach-omap1/clock_data.c b/arch/arm/mach-omap1/clock_data.c index 201b1f2..e616042 100644 --- a/arch/arm/mach-omap1/clock_data.c +++ b/arch/arm/mach-omap1/clock_data.c @@ -16,6 +16,8 @@ #include <linux/kernel.h> #include <linux/clk.h> +#include <linux/cpufreq.h> +#include <linux/delay.h> #include <linux/io.h> #include <asm/mach-types.h> /* for machine_is_* */ @@ -928,7 +930,9 @@ int __init omap1_clk_init(void) void __init omap1_clk_late_init(void) { - if (ck_dpll1.rate >= OMAP1_DPLL1_SANE_VALUE) + unsigned long rate = ck_dpll1.rate; + + if (rate >= OMAP1_DPLL1_SANE_VALUE) return; /* Find the highest supported frequency and enable it */ @@ -942,4 +946,5 @@ void __init omap1_clk_late_init(void) } propagate_rate(&ck_dpll1); omap1_show_rates(); + loops_per_jiffy = cpufreq_scale(loops_per_jiffy, rate, ck_dpll1.rate); } -- 1.7.3.4
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